Variable-speed drive mechanism



Dec. 30, 1952 w. B. HERNDON 2,623,411

VARIABLE-SPEED DRIVE MECHANlSM Filed June l, 1950 3 Sheets-Sheet lGttornegs Dec. 30, 1952 w. B. HERNDON 2,623,411

VARIABLE-SPEED DRIVE MECHANISM Filed June l, 1950 3 Sheets-Sheet 2lwentor Gttornegs Dec. 30, 1952 w. B. HERNDoN 2,623,411

VARIABLE-SPEED DRIVE MECHANISM med June 1, 195o I5 Sheets-Sheet I5?Patented Dec. 30, 1952 lVARIABLE-Sl?EED DRIVE MECHANIYSM y'WalterB.-Herndon, Rochester,'Mich., assignorto General Motors Corporation,Detroit, Mich., a

tt-corporation goh-Delaware `"Application J unel, 195 0,` Serial No.165,536

.19Glaims. 1

This invention `relates to `|combinations of gearing with multi-ple`rotor torque converters whereinthere are plural, independentlyrotatable turbine members separately connected to gear elements of achange speed geartrain, -for thepurpose of obtainingautomatic -changelofdrive ratio through thedi-ffering velocity characteristics of theturbine members.

The invention discloses a iixed countershaft type of gear train havingtwo input gears each connected to a different turbine member with theoutput portion -of the Vtrain connected to theload shaft throughautomatic-andfotherwise controllable clutch means.

The useful result of the arrangement is a drive mechanism `capable `ofAproviding a wide range of speed ratio drive -automatically selected bythe torque and speed conditions ofthe torque converter for all speedratioslbelowdirect drive, the drive mechanism including anfoverrunningclutch for eliminating the drive of the torque converter `when itstorque-multiplying combination with the gear train is notneeded.

The invention `specifically embodies a `fluid turbinedevice consistingof four rotors including one impeller driven'by a `power source, twotorque-transmitting rotors, `one "of iwhich is bladedto rotate at higher.speeds than the impeller under initial drive conditions, `the other ofwhich is bladed to rotate atv lower speeds than the impellerlduringforward reduction driveifollowing initial drive, andthe `fourth rotorforming a reactionmember held against vreverse rotation bymeans of va`one-way brake. The nrst rotor is arranged .toffurnish a primaryreduction f.

range torque component to :a novel gear train, and is connected to a`gear element through Aa oneway clutch. The second driven rotor isadapted'to furnish a secondarycoupling component to thegear train, andis directly connected to its driven vgear element. The Vfourth rotatableelement ispositioned intermediate the impeller; and Vsecond driven`rotor,` and is adapted for forward vrotation but, as stated, is heldagainst reverse rotationby means of a one-.way brake, so `that it'imayact as a reaction element under certain conditions of operation. Itwill, of course, beiunderstood that the impeller, two driven "rotors,and rreaction element form a toroidal chamber for circulating workingfluid, the blades of the various elements being exposed to thecirculating fluid.

' The A gear train `embodied in1this invention includes a cluster roftorque transmitting gears xedly -secured'to a common countershaft, one

of said countershaft gears beinginmesh with` a. gear driven by the rstrotor and the other countershaft gear being in mesh with avseconjd geardriven by the second of the rotors. Torque output from the countershaftis coupled Vto a load shaft through a forward gear drive or a reversegear drive train as desired. A clutchis provided whereby the torque iiowfrom lthe countershaft may be cut off from the nal load shaft. Anadditional clutch is provided whereby the torque converter may beby-passed to establish direct drive between the engine shaft and l-oadshaft.

It is an object of this invention to provide intheabove stated drivesystem a primarylforward reduction drive through the torque-deliveryacti-on of the first driven rotor and a countershaft effective to rotatethe second driven rotor during initial drive conditions, and a secondaryreduction drive through the torque-delivery action of the second drivenrotor and the countershaft, the first driven rotorbeing coupled to thecountershaft by means of a one-way clutch effective to disconnect therst driven rotor'from the countershaft during torque delivery'by thesecond driven rotor, whereby the first driven rotor is enabled to rotatefreely in the rotor working chamber. This action permits the rst drivenrotor to offer minimum resistance to the flow of circulating fluid inthe rotor working space and is advantageous in that it producesautomatic transition from 'initial 'low forward drive range to a secondspeed ratio range.

Other objects and advantages of this `invention include the provision of,special forms `of drive mechanism, in particular the use of onewayclutches in the drive connections of the rotors'to certain of the gearelements, and the furthervuse in the combination of a special form offriction clutch having a high torque capacity and adapted to be operatedby uid pressure medium.

Additional objects and advantages of this inventioniwillbe apparent fromthe following description and claims taken lin conjunction with theaccompanying drawings in which:

Figure 1 is a verticallsection of na ytransmission assembly constructedin accordance iwith the principles of thisinvention.

FigureZ is a similar section of a clutch mechanism for connecting thedrive elements atithe right of Figure 1 to a load shaft.

Figure 3 isa detail section of a special clutch construction of the gear`train of Figurel.

Figure 4 is a partially sectional view of an alternate clutchconstruction shown in Figure 3, showing a novel torque assist-clutchoperator and actuator mechanism.

Figure' is a modification of the torque converter shown in Figure l,illustrating fluid pressure inlet and outlet passages to and from theconverter.

Referring to Figure 1 there is shown an engine snait I for driving aflywheel structure 2, the latter consisting of a spring plate 3, clutchcylinder plate li, fitting and a drum 6, the fitting being bolted toboth the clutch plate and drum and the spring plate being bolted to thefitting and engine shait. Drum 6 is attached to and carries an impeiler'i' of a fluid torque converter W. A sleeve 8 secured to the hub end ofdrum 7 is splined to a gear 3 of a servo pump P which provides a sourceof fluid pressure for actuating fluid servo mechanism hereinaiterdescribed.

A nrst driven turbine rotor member II is provided with a plurality ofblades lia which occupy the outer periphery of the converter workingchamber to bridge the converter oil outflow and iniiow zones designatedas a: and y. Rotor II, driven by the fluid body such as oil within theconverter acting upon blades Ila, drives a hollow shaft I5 through aone-way clutch composed or members i2 and I4 forming a race for lockingelements I3, member I4 being splined to shaft I5 and member I2 beingsecured to member II.

A second turbine rotor element I6 occupies the ini'low zone of theconverter working space except ror the extreme inner radial portionwhere stator I'I bridges the space between the oil inflow and outflowzones. The rotor I6 is carried by a hub Iii splined to hollow turbineshaft 20 having a gear 28 integral with the shaft at one end thereof.Stator il is mounted upon a hub Ilo and carries passage forming bladesIla for directing fluid from zone y to zone 1t. The stator Il is heldagainst backward rotation by means of a one-way brake composed of a ringmember 2l, member 22, and locking elements 23. lVlembers 2I and 22 arespaced from each other to form a raceway therebetween in which theoneway locking elements are placed. Member 2I is carried by hub I'Ib xedto member Il, while member 22 is formed on a sleeve member 24 formedintegrally with a housing web portion Illua and xed against rotation. Apair of pump gears 3-I3 are enclosed in a pump chamber formed by web Iaand a second web Iiiilb extending interiorly from housing Ill.

An inner load shaft 56 is splined to a clutch hub 26 which, in turn,carries a clutch plate 25. The shaft 50 extends to the right in Figure 1and forms the output member of the transmission assembly. The hollowshaft I5, intermediate shafts 26 and 56, is keyed to a gear 2 adjacentthe right hand end of the shaft. A countershaft 36 carried in bearings36a and 36h is formed to provide four gear elements 3l, 32, 33 and 34.Gears 3I and 32 are placed in constant mesh with gears 2l and 28,respectively, while gears 33 and 34 constitute the low and reversetransfer gears, respectively. A gear body 35 meshing with gear 33 iscoupled to a sleeve member 36 by means of a one-way clutch composed ofspaced members 31 and 39 having locking elements 38 disposedtherebetween, the sleevemember 36 being toothed at 4I to engage internalteeth 42 of a slide gear 43 positioned for axial movement along a sleeve46.

As shown in detail in Figure 3, a drum member 45 splined to sleeve 36forms a cylinder p0rtion 46 adapted to receive a piston 44 positionedfor longitudinal motion in the cylinder and pinned to the cylinder bymeans of a pin 45a. Gear 43 is splined to sleeve 46 and may be movedrearwardly to disengage teeth 4 I-42 and to mesh with an idler gear llmeshing with countershaft output gear 34 of Figure I. Cylinder 46 isprovided with a cone ring 5I fastened to the inner peripheral wall ofthe drum to act as a clutch backing member. A projecting extension 52 onpiston 44 is of cone shape externally to mate with an inner conic faceof a cone ring 53 splined to gear 35. The outer face 54 of cone ring 53is of cone shape to engage the inner conic face of ring 5I. Fluidpressure in cylinder 46 shifts piston 44 to the right to clutch gear 35to sleeve 36, which sleeve in turn is connected to gear 43 when theteeth II- 42 are engaged. Sleeve 46 is clutched to shaft 58 by means ofa clutch K hereafter described and shown in detail in Figure 2. A springwasher 44a acts to detach the cone surfaces of members 52 and 53 whenfluid pressure is released from cylinder 4U. Engagement of fluidpressure actuated clutch 5I, 52, 53 serves to by-pass the normal effectof one-way clutch 3l, 38, 33 so as to provide two-way drive in both lowand second speeds. Fluid pressure to cylinder 46 is provided by passageIIlI, port |02 in the sleeve of drum 45, and passage |63, and iscontrolled by external valving.

Casing |83 extends to the right, and as shown in detail in Figure 2,contains a rear clutch unit K. Load shaft 56 protrudes from the rear ofcasing ISD for attachment to the nal driven mechanism, and is supportedby bearing 68 in web member Illc. A composite clutch drum 6) is splinedto shaft 50, the clutch drum being formed internally to provide acylinder 62 to accommodate a piston 6I. Piston 6I is shaped to provide atapered surface 63 adapted to mate with face 64 of a conic plate 65,plate 65 being mounted upon a hub 6'! splined to shaft 46. A backingcone 66 is keyed to the inner cylindrical portion of drum 60. Piston 6Iis pinned to drum 6I] by means of pin 68.

A passage 'il in casing Id communicates through port Ha, passages 72,73, 74 and passage 75, see Fig. 1, to admit fluid pressure to cylinder8i) to cause piston 82 to apply direct drive clutch 25. Passages 16,port 16a, passage ll, and port 'I8 are provided to admit fluid pressureto cylinder 62 to apply clutch K. As shown in Figure l, piston 82a ispinned to cylinder plate 4 by means of a pin 83a so that torque may betransmitted from cylinder plate 4 to hub 26 when the clutch 25 isengaged.

A pump Q composed of meshing gears SI and 82 is supported upon webIIJllc, being housed between web I 66o and a casing member 83 and isdriven by the sleeve of drum 6D, the sleeve being keyed to gear 32. Asplined tooth member 85 splined to shaft 56 rearwardly of bearing 68serves as a drive gear for a control governor, the teeth 86 of gear 85being positioned to cooperate with apawl 36a for locking the gearagainst rotation to provide a parking brake. Pawl 86a may be manuallymoved into and out of engagement with gear teeth 86.

Operation tained by the multiplied torque of the first turbineorlfrotoril I driving shaft I through oneway clutch I,2I3 I4, shaftI5,.in turn, driving countershaft through gears Z'I--SL Power from`countershaft 30 is transmitted to sleeve 3B through gears 33 and 35 andone-way clutch 3l, 38, 39. The pov/er then flows through teeth III-42,gear 43 to sleeve 46 and finally to shaft 5U through clutch K when theclutch is engaged. When clutch K is disengaged, no power may betransmitted from the torque converter to load shaft 50 and thetransmission is in neutral except when direct drive clutch D is engaged.During the initial drive in low gear, the second turbine or rotor I6does not receive sufcient torque from the circulatory velocity of thefluid body of the turbine working space to provide drive through sleeve2D Yand gears 28-32. Consequently, drive is solely through sleeve I5,gears 2'I3I `and the train as stated. During this interval, the`non-driving gear train 32--28 spins shaft 2G and the second turbine I5at a speed determined vby the ratio of the dimensions of gear trains2'I-3I and 32-28. Assuming finite values for the gear diameters of thevarious gears in the transmission, for example;

Gear Diameter 21 20 23 25 3| 24 32 19 33 14 35 29 and the rotation ofshaft I5 to be five hundred revolutions per minute, for example, wouldturn shaft 3U at eig of this speed or 417 revolutions per minute, andshaft 2i] would idle at 1%5 of this speed or approximately 315revolutions per minute. The blading of impeller 'I is so designed withrespect to the blading of turbines I I and I6, that it is possible tooperate the vehicle in the described overall low gear drive by means ofturbine II up to a vehicle speed of approximately ten miles per hour atreasonable efhciency, since the gear ratio of approximately 2.48 betweenshafts I5 and 5I) is augmented by the reduction ratio of the torqueconverter itself, which by design may easily provide a 1.5 furtherreduction to yield an overall net low drive ratio of approximately 3.72.This overall reduction is comparable with the current practice in thedesign of the low gear ratio in a conventional three-speed transmission.It should be noted that a fluid torque converter which is inherentlycapable of very low speed reductions below 3 to 1 is much less eiiicientthan a converter having less reduction ratio. However, by obtainingpartial speed reduction through the countershaft, eiiicient operation isobtained.

Because `of the peculiar rotation relationships of rotors II, IB and II,during initial drive the reaction rotor I'I is urged to rotate backwardbut is held against such rotation by one-way brake 2I-22-23. At thistime interval rotor II, through one-way clutch I2--l3-i4, vdrives shaftI5 and gear 2l at a primary torque multiplication, the gear train2'I-3I-3335 driving shaft 5i! at a further torque multiplication. Theresulting low gear drive is fully adequate for any inclines, howeversteep, that may be encountered in operation of the vehicle. Since thegears 32-28 are at this time spinning shaft 20 at a multiple of thespeed of shaft I5, rotor l5 is forced to rotate forwardly, for example,at approximately .63 ofthe speed ;of rotation. of Vshaft Cil I5. Ifrotor I3 were braked againstrotatiomrit would provide a stator effect tothe iiow of circulating fluid and direct the same for entry into theinlet space of impeller "I, but since it is required to rotate forwardlyupon rotation of impeller II, it may be said to act as a forwardlyrotating reaction member. Further re-direction of the circulating uidstream is provided by the blades of member Il which acts as a statorduring the interval when its backward reaction torque component, appliedby the circulating fluid, is effective to lock the one-way brake 2 i--22,-23 to thereby prevent Vbackward rotation of the member.

As rotor II increases its rotational speed, the circulating velocity ofthe fluid delivered by impeller I i falls off until it reaches a given.value whereupon the second turbine lli is overtaken by uid action andcan no longer idle. A coupling torque is developed upon the rotor I6tending to drive the vehicle through the second speed gear train 2S-32-This torque, tending to increase the speed of rotation of countershaftV33 over that applied to the shaft through gear train 2`I-3l, also tendsto spin shaft I5 through gear train til-2T at a ratio inverse to that bywhich shaft I5 formerly drove shaft 2t, or, as in the example cited, atan overspeed of about 1.59. Under the condition of operation, thecirculating fluid is unable to rotate turbine rotor I I at sufficientspeed to deliver torque to shaft I5, so that shaft iii is rotated atgreater speed than the turbine iI, the one-way clutch I2-3Id releasingto uncouple shaft I5 from turbine I I.

Since both torque converter rotors II and it lie in the circulatingfluid stream of the turbine, their respective rotational speeds dependsupon load applied (resistance to rotation of shaft 5t) and upon thedifferential speed of each rotor and the impeller. Release action ofone-way clutch lZ-Efllt, however, is controlled by overtaking speed ofshaft l on one hand and jointly by input torque applied to rotor ll androtational speed of rotor II on the other hand. Thus, it is found thatduring the transition interval, both rotors II and I6 are momentarilydelivering torque, providing an interval of torque overlap. The gradualnature of this action prevents shock on the one-way clutch elements,since the clutch elements not only engage but also release underdefinite minimum changing torque conditions and are never required tolock or release with one member running completely free.

With one-way clutch ii-iS-Ei unlocked, drive is in second gear, theoverall value of the reduction ratio being determined by the dirnensions of the gear train and the blade design of the converter foroperation with turbine l@ acting as the sole driving member. This isreadily calculated with the example figures given above, the gearreduction ratio being approximately 1.59 and the converter ratioapproximately 1.5, yielding a net overall reduction ratio ofapproximately 1.92 from engine shaft I to output shaft 5t. is a veryacceptable second speed ratio in present practice. It will readily beunderstood that the above described operation in low and second `drivingranges could continue automatically endlessly without attention of theoperation of the vehicle since the drive range, either low or second, isobtained automatically through .the drive selection occasioned by thefirst and second driven rotors as they accept torque from the fluidstream.

l On. .downshit from secondzspeed,range,;under 1 This load, the loadapplied to rotor I6 through gears 32-28 and shaft 20 causes thecirculating velocity of the fluid in the converter working space to riseto a value capable of imparting torque to rotor ll suicient to cause therotor to overtake shaft I and lock one-way clutch l2-l3--l4, at whichtime turbine it ceases to provide torque and the drive is in low ratio.This normally occurs at low output shaft speed. Under normal overtakingtorque in second speed range (due to deceleration of the vehicle atspeeds above ten miles per hour in the example given) there is noautomatic downshift to low range. If, however, throttle advance occursat such a period as when the development of impeller-induced fluid flowis in the range where the first driven impeller can deliver torque,drive will be in low range.

A further feature of this transmission is the automatic attainment of acoupled drive ratio by the converter, due to the selected blading ofform of the various rotors. At a selected circulating velocity of theturbine fluid, the stator blades ila no longer receive a directionaliiow from rotor I5 tending to lock the one-way brake 2 l-2 2-23, and thefluid stream impinges on the convex backs of the blades lla, therebytending to cause member Il to rotate forwardly. The torque converterreduction ratio thereafter approaches a one-to-one ratio between theengine shaft I and the converter output. Thus, whenever member l'l' iscaused to rotate forwardly, the torque converter no longer acts as atorque multiplier but, rather, transmits torque in a manner similar to afluid flywheel. This action may, by design, be -caused to occur in firstor second speed ranges, or both, but it is preferred that in the presentstructure the shift to top converter ratio take place only when theturbine rotor I6 is transmitting torque in second speed range.

This invention, therefore, makes it possible for the driver of a vehicleto enjoy fully automatic shift from initial drive through low and secondspeed ranges up to the gear ratio of the second speed gear train ofapproximately 1.59 to l when the converter ratio is at approximately 1to 1 without the use of any controls, and solely as a result of theinherent action of the described parts. t is believed that for operationof vehicles under difficult trahie conditions, the invention contributesto smooth, effortless drive control and to public safety.. it reducesthe number of controls requiring attention of the operator and by virtueof the inherent overtaking action of the turbines in automatic selectionof drive ratio, minimizes the cost as compared with other automaticcontrols. Another apparent advantage is the unusual smoothness of drivetransition accomplished without the use of power or other application offriction elements such as planetary reaction brakes, or of ratioclutches. common in this art.

It is believed novel to utilize the torque characteristics of twoindependently rotatable converter ratios to obtain torque multiplicationin two separate gear trains, and wherein an automatic stator effect andstator release is provided in the torque converter.

Referring further to Figures 1 and 3, the slidable gear 43, may haveonly three effective positions; a forward position in which teeth l2engage teeth 4l of sleeve 36, a central neutral position, and a rearposition in which the teeth 43 mesh with a reverse idle gear 41. Anysuitable means, such as a shift fork (not shown) actuated by a mastercontrol adapted to be placed in either aforward, neutraL or reverseposition may be utilized to place the gear 43 in forward, neutral, orreverse condition of operation. Clutch K, heretofore described, iseffective at all times when cylinder 62 is exhausted, to provide apositive neutral whereby creep of the vehicle due to rotation ofimpeller l and countershaft 3i] may be avoided. Thus, clutch K may bedisengaged by lack of fluid pressure when the master control is placedin neutral and slider gear i3 may be positioned in forward mesh withoutdanger of vehicle creep. Upon movement of the master control to eitherforward or reverse position, external valving of any suitable type (notshown) may be actuated to admit fluid pressure to passage 15 and 16 andto cylinder 62 to move piston 6l to cause conic plate Si to be grippedby drum 6B to establish drive between shaft 'it and shaft 50.

It will likewise be understood that suitable external valving may beactuated by the master control or by automatically operableV valvingmechanism to admit fiuid pressure to cylinder 3B as shown in Figure l tocause piston 82 to grip clutch plate 25 (attached to shaft 50) to theflywheel assembly. With clutch 25 engaged to member 5 of the flywheelassembly, engine torque is applied directly to shaft 59 and sleeve 35may be driven faster than gear 35, unlocking one-way clutch 3lt839 sothat the gear trains idle without load. Release of the direct driveclutch 25 and resumption of torque transmission by the torque converterautomatically establishes the automatic converter combination driveheretofore described. Under overtaking torque, with shaft Si) rotatingfaster than gear the drive freewheels due to action of one-way clutch3l-38-39, and the release of torque on the converter rotors permits thevelocity of the circulating iiuid to fall, following which theresumption of drive torque restores the circulating velocity of theworking fluid in the converter and automatically sets up drive action ofrotors Il and IE in accordance with their torque capacity at thatvelocity.

The recited freewheeling or coasting effect may not be desired undercertain driving conditions as, for example, when engine brakingassistance is desired in descending a steep grade. Accordingly, meansare provided to bypass or block the freewheeling action of one-wayclutch 3?-33-39. Fluid pressure may be admitted to cylinder space Iii]behind piston d4 by means of passages lill, |82 and l, the passage IlJIbeing connected to suitable external valving which may be actuated bythe positioning of the master control to admit pressure to passage Il.Pressure admitted to passage ll loads the friction faces of conic ring52 on piston C14 and cone ring 53, thereby gripping sleeve 36 to gear 35for two-way drive as distinct from the one-way action of clutchSl-SB-SSL Release of this pressure, as may be accompanied by movement ofthe master control, re-establishes the freewheeling condition, thesprings lilla acting to return piston ill to the left to disengage thegripping surfaces.

Shift to direct drive through application of clutch 25 is preferablyattained by the use of suitable selector valves (not shown) which may beautomatically actuated in response to pressure relationships acting uponthe valves as may be determined by throttle position and governorYDressuragthelatterfbeing responsive to speed of rotation of theV outputshaft 50. The gear 85 of Figure 1 may be used to drive a uid pressuregovernor (notshown), the governor being connected `by suitable pipingtopumps P and Q and to `the selector valves. The selector valves, in turn,are-connected to the vehicle throttle and tothe cylinder ad foradmission of uid pressure to the cylinder.

Agear 35 on shaft 5t is provided with teeth Eiwhich may cooperate with asuitable pawl mechanism 86a to provide a positive parking brake for thevehicle.

Referring to'Figure 4, there is shown an alternate` clutch and shaftarrangement which may be` substituted for the mechanism shown in Figure-3. The modincation is particularly adapted for coupling a pair of torqueoutput shafts; the-shaft .de being an intermediate shaft driven by-thecountershaft 3d of Figure 1 in the same-,manneras shaft 5t of Figure 1.That is to say, intermediate shaft 551 may be driven through thecountershait 3l)` by either turbines HV or I5, or may be` directlyconnected to the engine `shaft by clutch 25. Afinal load or torqueoutput shaft mi is` journaled into the end of shaft ilfas shown.

An external gear, 9|` having teeth Sia is carried by aisleeve 92 splinedto shaft Si) with oneway clutch locking members @Stintermediate thesleeve and gear for providing one-way drive of shaftii,f fromcountershaft Sii. Gear 9|, in the complete assembly, meshes with gear t3of the countershaft- 3?. and is rotated upon rotation of` thecountershait to apply torque from the countershaft to shaft Edi. Anextension 94 xed to, gear 9|` is formed` with aconical clutch surface-95facing. and adapted to mate with a conical clutch surface te, formedupona piston Si', the piston being pinned by a pin 97a toa housing 98splined to shaft 55 for rotation therewith. The housing is shaped toform a cylinder. 519 for receiving piston il?, which cylinder mayreceive fluid pressure through ports I Ill and I I I; the latterconstituting an annular grooveon the periphery of shaft 96 andcommunicating with an external source of huid pressure. When fluidpressure is admitted to cylinder i3d, clutch @ii-6 ties gear 9| directlyto housing 93, thereby by-passing the one-way clutch to establishtwo-way torque transmission between shafts 5G and 93.

A second cylinder H2 formed` by housing 98 isl adapted4 to receive asecond piston H3, the latter piston` including an extension Hli` havinga plurality of spaced inwardly extending clutch plates 4Hd keyedthereto. A clutch drum Ht splined to iinal load shaftl @il carries` aplurality of outwardly extending spaced clutchplates Hi disposed`adjacent clutch plates l5. An inwardly extending clutch plate backingmember Hii4 is carried by housing et for supporting the clutch platesupon movement of piston H3 for clutch engagement. Aball Hb positioned ina diamond shaped ball receiving pocket formed by ball socket Hita and asimilar socket I9 formed.

on piston I I3 serves as a torque-assist mechanism as hereafter furtherexplained. While only a single ballis shown, itA will be understood thata series of such balls may be spaced around the piston H3. When iuidpressure is iirst applied to cylinder H2, andv at the point of initialengagement of the clutch plates, piston H3 is, or mayA be, rotating ataspeed different from that of` clutch drum H. Due to the relativelydifferentl speeds of rotationA of these members, a

twistis applied to piston I3, which twist, though slight, sets upareactive force or load on the balls, which balls, in turn, apply thereactive load to the face of the piston adjacent `the balls. Thereactive` load, in turn, is transferred from theballs throught the,piston so that it is felt onthe outer set of` plates. In this manner,there is provided a torque-assist structure for engaging the plates`whereby a smoother and morepositive. clutch engagement is achieved andwhich contributes greatly. toincreased clutch platelife. Fluid pressuremay be admitted` to cylinder H2 through ports |29` and I2| communicatingwith the. interior. of hollow` shaft Sii drilled out at |22.

Suitable valving, not shown, may be used to control the admissionandeXhaust of iiuid pressure toy and; from vcylinders 99 and H2. ClutchStr-95, is normally engaged to disable the action of one-way clutch9|-82-93 whenever engine braking through the torque converter isdesired, as in descending steep grades. Clutch plates H-H'i are engagedto provide torque transfer between shafts 5S and eiland disengagedtoprovide positive neutral irrespective, of whether the drive of shaft501s through the countershaft or directly from the engine as is thecasewhen clutch.25 ofFigure 1 is engaged.

As shown in Figure 5, fluid under pressure `may be admitted to thetoroidal working chamber formed by the blades of the rotatable membersof the torque converter by means of fluid pressure inlet pipe |25communicating through passages |26, |21, |28 and space |29 intermediateimpeller and reaction member with the central portion |30 0f theconverter. At the same time, this iiuid under pressure passes throughspaces I 3| and |32 to opposite sides of rotor H (spaces |3|a and |32a)and outwardly from the converter through passages |33 and |36, pipe |31which pipe may constitute a lubrication feed passage for lubricating thetransmission. A pressure relief valve |38 is used to regulate thepressure of lubrication feed at any desired pressure, such as, forexample, twenty poundsper square inch. A restricted orifice |39 inoutlet pipe |31 permits the pressure in the torqueconverter to bemaintained at its desired pressure, such as, for example, eightyl poundsper square inch. Input line |25 is connected through suitable piping(not shown) to the outlet of pumps P and Q of Figure 1..

Pipe |40 is connected to passage 'M so that uid pressure may be admittedto cylinder to apply direct` drive clutch 25 as heretofore explained.`

It will be apparent from the foregoing description of the invention thatthe construction is advantageous in that there are no transmissionnoises in neutral" since there is no relative gear motion and thatreversev may be obtained without by-passing the one-way low gear clutch31, 38, 353, while making it possible to obtain both low reverse andsecond speed reverse ratio by the automatic upshift action of turbinemembers H and I6. A further advantage is that thearrangement permits afree towing of a disabled vehicle, whether or not slide gear 43 ismeshed with teeth 4| of sleeve 36, and alsopermits connecting of thedrive for starting a stalled engine by towing the vehicle in directdrive by engagement of clutch D or` in a lower gear ratio by.engagement. of clutch K and actuation oflclutch G. The pumps-P andQ bothprovidej fluid pressure for lubrication; for.` filling the. converter.

working space, and for actuation of the three clutches. This pressureis, of course, available whenever either the engine shaft or outputshaft is rotated.

The cone clutches and the multiple disc clutch shown are of thefree-releasing and high-load type, permitting high torque capacity in asmall space. The nested gear arrangement in combination with the pluralconverter turbines and one-way clutch is believed novel and ofparticular utility in obtaining automatic change of drive ratios withoutthe need for external governors and equivalents. Since the point ofratio upshift from low to second involves inherent torque capacities ofeach of turbines Il and is for a given range of tordues, expressed ascirculating velocity of the fiuid body of the converter working space,and involves the net gear ratios of the connected gearing with respectto the vehicle load. there is particular merit in combining a doublepair or nest of transmission input gears in the manner described. Bythis arrangement the nested parts may conveniently be placed beneath aflat floorboard in the drivers compartment while having a large portionof the transmission projecting thereunder.

Having described the preferred embodiment of this invention and possiblemodifications thereto, what is claimed is:

l. In a variable speed drive mechanism for connecting a power inputshaft to a load shaft, a iiuid turbine device having an impeller drivenby said power shaft, a pair of toroue-transmitting rotors, Va reactionelement, said turbine, rotors, and reaction element being bladed to forma working chamber for a circulating iiuid body, a countershaftoperatively connected to each of said rotors, and drive coupling forconnecting said countershaft to said load shaft.

2. In a variable speed drive mechanism, a power input shaft, a loadshaft, a fluid turbine device having an impeller driven by said powershaft and a pair of tordue-transmitting rotors, a reaction element, saidmpeller reaction element and rotors being bladed to form a workingchamber for a circulating fluid body, a countershaft operativelyconnected to one of said rotors, oneway clutch means connecting saidcountershaft to the other of said rotors, and drive couplingr forconnecting said countershaft to said load shaft.

3. In a variable speed drive mechanism, a power input shaft, a loadshaft, a fluid turbine device having an impeller driven by said powershaft, a pair of torque-transmitting rotors and a. reaction elementbladed to form a working chamber for a circulating fiuid body, acountershaft, gear means connecting one of said rotors to saidcountershaft, gear means connecting the other of said rotors to saidcountershaft, a oneway clutch intermediate one of said rotors and saidcountershaft, a one-way brake for preventing reverse rotation of saidreaction member and for permitting forward rotation thereof, and gearmeans connecting said countershaft to said load shaft.

4. In a variable speed drive mechanism, a power input shaft, a loadshaft, a fluid turbine device having an impeller driven by said powershaft and a plurality of rotors, said impeller and rotors being bladedto form a working chamber for a circulating fiuid body, a countershaftoperatively connected to said rotors, gear means connecting saidcountershaft to said load shaft, and

a one-way clutch intermediate said gear means and said load shaft forestablishing one-way drive between said shafts.

5. In a variable speed drive mechanism, a power input shaft, a loadshaft, a fluid turbine device having an impeller driven by said powershaft, a pair of torque-transmitting rotors and a reaction member, saidimpellers, rotors, and reaction member being bladed to form a workingchamber for a circulating uid body, a countershaft operatively connectedto said rotors, gear means connecting said countershaft and load shaft,a one-way clutch intermediate said gear means and said load shaft forestablishing oneway drive between said last-mentioned shafts, and asecond clutch operable to establish twoway drive between saidcountershaft and load shaft.

6. In a variable speed drive mechanism, a power input shaft, a loadshaft, a fluid turbine device having an impeller driven by said powershaft and a pair of torque-transmitting rotors, said impeller and rotorsbeing bladed to form a working chamber for a circulating fluid body, acountershaft operatively connected to each of said rotors, meansconnecting said countershaft to said load shaft, and clutch means forselectively connecting said engine shaft to said load shaft andrendering ineffective torque transmission through said turbine.

7, In a variable speed drive mechanism, a power shaft, a load shaft, aiiuid turbine device having an impeller driven by said power shaft and apair of torque-transmitting rotors, a hollow shaft having a gear aiiixedthereto, a second hollow shaft having a gear affixed thereto, meansconnecting each of said hollow shafts to one of said rotors,respectively, a countershaft, a pair of gears on said countershaftmeshing with said afore-mentioned gears, respectively, an output gear onsaid countershaft, a sleeve member, said sleeve and said hollow shaftsbeing concentric with respect to each other, gear means carried by saidsleeve member meshing with said countershaft output gear, and meansconnecting said gear means to said load shaft.

8. In a variable speed drive mechanism, a power input shaft. a loadshaft, a uid turbine device having an impeller driven by said powershaft and a pair of torque-transmitting rotors, a hollow shaft driven byone of said rotors having a gear aiiixed thereto, a second hollow shaftdriven by the other of said rotors having a gear affixed thereto, acountershaft, a pair of gears on said countershaft meshing with saidaforementioned gears, respectively, an output gear on said countershaft,a sleeve member, said sleeve and said hollow shafts being concentricwith respect to each other, a gear carried by said sleeve member meshingwith said countershaft output gear, clutch means connecting said sleevegear to said load shaft, and clutch means operable to selectivelyconnect said power input shaft to said load shaft and renderingineffective transmission of torque throughV sai rotors.

9, In a variable speed drive mechanism, a power input shaft, a loadshaft, a uid turbine device having an impeller driven by said powershaft anda pair of torque-transmitting rotors, a first gear driven byone of said rotors, a second gear driven by the other of said rotors, acountershaft, a pair of gears on said countershaft meshing with saidlfirst and second gears, respectively, an output gear on saidcountergearsaidgearA being; movable axiallyalong said second sleeve andsaid idler gear for forward, and reverse drive respectively,` of saidload` shaft, and meansconnecting said second sleever to said load shaft.

10,r In aA vehicle drive. mechansm, a power 1nput. shafaa load shaft,` afluid turbine device having an imp eller4 drivenby said power shaft andapair of: torque-transmitting rotors, ai first gearV drivenby oneof saidrotors,` aisecond gear driven` by the othern of said.rotorsacountershaft, a ipair` of gears. on; said countershaft mesh.- ingwithsaid first and second gears, respectively, alcountershaft output'V gear,a: iirstlsleeve, a gear carried by, said sleeve4 meshing, withsaidcountershaft outputagear, acne-wayclutch for con,- necting said sleevegear tosaidisleeve, gear teeth on said sleeve, a second sleeve, a secondoutput gear on said countershaft, anidlergear. meshing with said secondcountershaft output gear, a gear splined to said,y second sleeve,l saidgear having one setof? teeth adapted to mesh with saidl idler gear and asecondset of teeth. adapted to mesh with said first sleeve gear teeth,said gear being movable axially along said second sleeve forselectively'engaging said rst sleeve and idler gear for forward orreverse drive, respectively, of

said load shaft, means connecting said second sleeve to said load shaft,and clutch means selectively operable for locking the first-mentionedsleeve gear to said first-mentioned sleeve for permitting two-way torquetransmission between said first sleeve and said countershaft.

11. In a variable speed drive mechanism, a power'inputA shaft, a loadshaft, a uidturbine device `having an mpeller driven by said power Shaftand a pair of torque transmitting rotors, a first gear driven by oneof'said rotors, a second gear driven by the other of saidrotors,acountershaft, a pair of gears on said countershaft meshing" with saidfirst and second gears respectively, acountershaft output gear, afirst`sleeve, a gear for rotating said sieve meshing with said countershaftoutput gear, gear teeth on said sleeve, a second sleeve, an idler gear,a second countershaft output. gear meshing with said idler gear,

a gear4 splined to said second` sleeve, said. gear having two sets ofteeth thereonand being, movable'axially on said second sleeve forselective engagement with said first sleeve gear teeth and said idler.gear, respectively, for forwardiorf re.- verse rotation of said loadshaft, and` clutch means for selectively connecting and disconnectingsaid second sleeve to and from said load shaft.

12. In a variable speed drive mechanism, a power input shaft, a loadshaft, a fluid turbine device having an impeller driven by said powershaft and a pair of torque-transmitting rotors, a rst gear driven by oneof said rotors, a second gear driven by the other of said rotors, acountershaft, a pair of gears on said countershaft meshing with saidfirst and second gears, respectively, a countershaft output gear, afirst sleeve, a gear for rotating said sleeve meshing with saidcountershaft output gear, gear teeth on said sleeve, a second sleeve, anidler gear, a

second countershaft:l` output, gear: meshing;` with said idler gear, agear splin'ed tor. said, second sleeve; said gear having two setsof'teeth thereon and being` movable axially on saidsleeve for selectiveengagement with said. rst sleeve gear teeth or withV said idler gear,respectively,y for forward or. reverse rotation` of said load shaft,clutch means for selectively connecting :and disconnecting said loadshaft to. and from said sleeve,` and additional clutch means forselectively connecting said power input shaft directly: to saidrloadshaft.

13. In a variable speed drive mechanism.` a power input shaft,anintermediate drive: shaft, a load shaft, a fluid turbine device havingan impeller driven by said power shaft anda pair, of torque-transmittingrotors, a first gear. driven by one of said rotors, a second geardrivenby the other. of said rotors,.a countershaft, arpair` of gearsonsaid countershaftmeshing withrsaid,

first. and second gears, respectively, a countershaft` output gear, gearmeans meshing,` withN said countershaft output gear'for rotating saidintermediate shaft, a clutch drum` housing splined to said intermediateshaft, and clutch means within said housing for selectively connectingand disconnecting said housing to and from said load shaft.

14. In ar variable speed drive. mechanism. a power input shaft, anintermediate drive shaft, a load shaft, a uid turbine device. having aniinpeller driven by saidpower shaft and a pair of. torque transmittingrotors, a first gear driven by one of saidrotors, a second gear drivenby the other of said rotors, a countershaft, at pair ofv gears cn saidcountershaft meshing with said first and second. gears, respectively, acountershaft output geen, gear. means meshingk with said counter-shaftoutput. gear forrotating said intermediate shaft, a clutchhousingsplined. to intermediate shaft and formed. to provide a cylinder, apiston in. said cylinder,` a plurality of clutch plates carried by saidpiston, a clutch drum splined to said loadshaft, and a plurality ofclutch plates keyed to said clutch drum adapted to engage saidrst-mentioned clutch plates upon movement ofsaid piston in,` saidcylinder.

15. In a variable speed drive mechanism, a power input shaft, anintermediate drive shaft, a load shaft, a duid turbine device having anim peller driven by said power shaft` and a1 pair of torque-transmittingrotors, a first gear driven by one of said rotors, aisecond gear drivenbythe other of said` rotors, a countershaft, a pair; of.

gears on said countershaft meshing with said first and second gears,respectively, a countershaft output gear, a gear meshing withA saidcountershaft output gear-for rotating saidinter'- mediate shaft, aclutch housing splined to said intermediate shaft andformed to provideacylin-V der, a piston in said cylinder, a plurality of inwardlyextending clutch plates keyed to said piston, a clutch drum keyed tosaid load shaft, a plurality of outwardly facing clutch plates on saidclutch drum adapted to engage said firstmentioned clutch plates, astop-member carried by said clutch housing a spring intermediate saidstop-member and piston normally urging said clutch plates intodisengagement, and a ball member intermediate said piston and housingfor transmitting reactive load on said piston to the outer set of saidclutch plates upon engagement of the clutch plates.

16. In a variable speed drive mechanism, a.

power' shaft, an intermediate drive shaft, a load shaft, a iiuid turbinedevice having an impeller driven by said power shaft and a pair oftorque transmitting rotors, a iirst gear driven by one of said rotors, asecond gear driven by the other of said rotors, a countershaft having apair or" gears thereon meshing with said gears, respectively, acountershaft output gear, a sleeve splined to said intermediate shaft, agear carried by said sleeve meshing with said countershaft output gear,a one-way clutch intermediate said sleeve gear and said sleeve forestablishing one-way drive between said countershait and intermediateshaft, a clutch housing splined to said intermediate shaft and formed toprovide a pair of cylinders, an extension on said sleeve gear, a pistonin one oi said cylinders having an extension adapted to engage saidsleeve extension, said eX- tensions locking said gear to said housingupon mutual engagement thereof for establishing twoway drive betweensaid countershat and intermediate shaft, a piston in the other of saidcylinders, clutch plates carried by said piston, a clutch drum splinedto said load shaft, clutch plates keyed to said clutch drums adapted toengage said piston clutch plates, spring means for normally disengagingsaid clutch plates, and a reactive member intermediate said piston andhousing for transferring reactive forces applied to said piston uponengagement of said clutch plates to the outer set of said clutch plates.

17. A uid torque converter comprising a plurality of independentlyrotatable bladed members, the blades of said members forming a toroidalworking space for enclosing a circulating fluid body, said space havingradial inflow and outflow Zones and inner and outer axial zones bridgingsaid radial zones, said converter consistlng of an impeller memberhaving its blades positioned in said outiiow zone, a rst turbine memberoccupying said outer bridging zone, a second turbine member having itsblades positioned in said radial inflow zone, a reaction inemberoccupying said inner bridging Zone, a gear unit adapted to connect saidturbine members to a load shaft through plural torque paths, said gearunit including a countershaft cluster gear and torque transmitting gearsdriven by said rst and second turbine members, respectively, meshed withmating gears of said cluster.

18. A fluid torque converter comprising a plurality of independentlyrotatable bladed members, the blades of said members forming a toroidalworking space for enclosing a circulating fluid body, said space havingradial inow and outflow zones and inner and outer axial zones bridgingsaid radial zones, said converter consisting of an impeller memberhaving its blades positioned in said outflow zone, a first turbinemember occupying said outer bridging zone, a second turbine memberhaving its blades positioned in said radial inflow zone, a reactionmember occupying said inner bridging zone, a gear unit adapted toconnect said turbine members to a load shaft through plural torquepaths, said gear unit including a countershaft cluster gear, torquetransmitting gears driven by said rst and second turbine members,respectively, meshed with the mating gears of said cluster and acountershaft output gear meshing with an input gear for driving saidload shaft, and clutch means for selectively connecting anddisconnecting said load shaft to and from said countershaft output gear.

19. In a variable speed drive mechanism, a torque converter comprising aplurality of independently rotatable bladed members, the blades of saidmembers forming a toroidal working space for enclosing a circulating uidbody, said space having radial inflow and outflow zones and inner andouter axial zones bridging said radial zones, said converter includingan impeller member having blades positioned in said outflow Zone, afirst turbine member having blades occupying said outer bridging zone, asecond turbine member having blades positioned in said inow zone and areaction member having blades positioned in said inner bridging zone, agear driven by said first turbine, a gear driven by said second turbinemember, a countershaft, and a pair of gears xed to said countershaft,said last-mentioned gears being in constant mesh, respectively, with thegears driven by said first and second turbine members.

WALTER B. HERNDON.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,055,895 Fawcett Sept. 29, 19362,235,370 Jandasek Mar. 18, 1941 2,260,015 Fichtner Oct. 21, 19412,280,015 Tipton Apr. 14, 1942 2,292,384 Lysholm Aug. 11, 1942 2,308,547Schneider Jan. 19, 1943 2,316,390 Biermann Apr. 13, 1943 2,317,498lTipton Apr.'27, 1943 2,321,672 Hall et al June 15, 1943 2,326,994Dufiield Aug. 17, 1943 2,383,980 Lysholm Sept. 4, 1945 2,397,368Pennington Mar. 26, 1946 2,402,164 Kelbel June 18, 1946 2,408,008 TiptonSept. 24, 1946 2,433,052 Kelley Dec. 23, 1947 2,466,206 Carnagua Apr. 5,1949 2,480,938 Lapsley Sept. 6, 1949 2,514,963 McRae July 11, 19502,529,400 Lapsley Nov. 7, 1950

